Fluid motor



PI WHITE FLUID MOTOR Filed llay 31, 1944 3 sh ets-sheetjli 8 I P. WHl TE2,332,526

FLUID mo'gon Filed May s 1, 1944- 3 Sheeis-Sheet 2 Patented Aug. 14,1945 UNITED STATES PATENT orrlcs FLUID MOTOR Percy White, Twickenham,England, assignor to The Automotive Engineering Company Limited,Twickenham, England Application May 31, 1944, Serial No. 538,119 InGreat Britain August 12, 1943 7 Claims. (Cl. 2532) drill should berotated at a very high speed (e g 15,000 a. P. M. or more) and that avery sensi tive feeding movement of the drill should be possible.

Drilling machines as at present in use for drilling very small diameterholes are adapted for a manual feeding of the drill by the operatoreither pressing a small lever or turning a knurled head and theobjection exists, in handling such machines, that the human elemententers into the obtaining of the feeding movement as it only re quires avery slight increase in pressure by'the operator on the control lever orhead to cause the drill to fracture.

The invention has for its object to provide an improved form of drillingmachine which can be employed to drill very small diameter holes andwhich dispenses with the necessity of relying upon the human element tomaintain the required sensitive feeding movement of the drill.

The invention consists in a drilling machine or head incorporating aturbine for rotating the drill spindle and means for controlling theturbine pressure to produce the drill feeding movement of the spindle.

The invention also consists'in a drilling machine or head wherein thedrill spindle carries the common rotor of a pair of turbines each havingits own jet and exhaust system and means is provided for restricting theexhaust from one or the other of said turbines to produce automaticallya feeding or retracting movement of the drill spindle.

In the accompanying drawings:

Figure 1 is an elevational view of one form of drill in accordance withthe invention,

Figure 2 is a longitudinal section of the drill according to Figure 1,

Figure 3 is an elevational view of the drill looking in the direction ofthe arrow A in Figure 1,

Figure 4 is a top plan View of Figure 1,

Figure 5 illustrates a detail, being a plug rotatable in the eX-haustbox of the drill to control the exhaust from the turbine chambers,

Figure 6 is a section on the line B--B of Figure 3,

Figure 7 is an end elevational view of the drill looking in thedirection of the arrow C in Figure 2,

Figure 8 is a view of a detail, being an underheath view of the blockseen in Figures 3 and 6 and containing the high pressure or inlet airassages,

Figure 9 is an end elevational View of a drill in accordance with theinvention equipped with an alternative exhaust system which involves theuse of a spring push-button valve for controlling end plate of theturbine casing containing the push-button valve,

Figure 12 is a side elevational View of Figure 9,

and i Figure 13 is a section on the line DD of Fig-: ure 12. In carryingthe invention into effect in on convenient manner and referring first tothe embodiment illustrated in Figures 1 to 8, a drilling machine or headis provided which can be employed to drill very small diameter holes andcomprises a spindle l (Figures 2 and 3) which carries a chuck 2 at oneend for the reception of the drill and is reciprocable withinaconcentric outer sleeve 3 which latter, at the end thereof remote fromthe chuck, terminates in an enlarged cylindrical casing 4 with respectto which the spindle is co-axial and in which an extension of thespindle carries, for rotation therewith, a disc 5 which extends radiallyfrom the spindle and virtually divides the interior of the said chamberinto two separate compartments 6 and to each of which constitutes aturbine chamber, the outer periphery of the said disc having only asmall Working clearance with respect to the inner cylindrical surface!of the casing.

The, turbines are conveniently ofthe Pelton wheel type and have theirbuckets constituted by vanes 8 disposed at the outer periphery of thedisc on each side face thereof, the blades of each ring thereofextending parallel with respect to the central longitudinal axis of thespindle.

The said extension of the drill spindle, at th end which is locatedwithin the said casing l, terminates short of the opposite end face 9 ofthe casing and the entire arrangement is such that the spindle I, withthe said disc 5 and two rings of turbine vanes 8 thereon, is free torespindle will be moved longitudinally either forwards or backwards.

For instance if the exhaust from one or the other side of the commonturbine disc 5 is restricted a pressure will be built up within theturbine chamber on that side and the rotor (-constituted by said disc 5and vanes 8) will. act as I a piston to move the drill spindle axiallytowards the opposite end. In particular, if the exhaust Irom the outerturbine chamber So, i. e. the

chamber farthest from the drill, is restricted, then a thrust will beapplied to the drill which is: proportional to the amount of therestriction and is; constant throughout the consequential axial travelofthe drill.

The desired effect, that is the automatic reciprocation of the drill orspindle by aselective controlling or the pressure in the two turbinechambers, can. be obtained in a variety of ways. If the effect isobtained by restricting the exhaust such restriction may, for example,be obtained by providing: an ordinary type of tap, similar to a gas tapin the exhaust system, or a push button combined with an adjustableby-pass orifice could be fitted to completely close the desired exhaustoutlet when the push button is depressed.

If the part, controlling; the restriction is fitted with an adjustablestop, then this can be set by a setter to give a pressure appropriate tothe size of drill in use and which cannot thereafter be exceeded by aless skilled person who may be using, the, drilling machine.

Further, if. the restriction is controlled by a mechanically drivendevice; such device can be made to oscillate the spindle at any desiredspeed, which would be particularly advantageous when grinding or lappinga small hole or clearing the swarf.

As a refinement it would be possible tofit a governor by which thedrilling speed could be adjusted to suit different sizes ofdri-ll whilemaintaining the full torque of the, turbine, which is not the case withthe usual method of regulating the speed by altering the air pressure.

Refierring to Figures 2., 3-, 6 and 8 the supply of compressed air todrive the turbine rotor is supplied througha central bore l contained.in a block H mounted upon the casing 4 by screws l2 and delivering intoa cross bore [3. containing a pair of branch nozzles I l,v Ma throughwhich the compressed air is discharged intothe turbine chambers 6, 6arespectively via pockets I6 formed in; the underneath surface of theblock H and openings L5 in the casing.

The exhaust of the air from the turbine chamher 6- takes place via ahole IT in the adjacent end wall ot the casing 4, which hole opens intoabore lid in anexhaust box H; which contains another bore 11b leadingfrom the bore [1c in the valve plug but perpendicular thereto anddischarging at its outer end into thev atmosphere. The exhaust of theair from the other turbine, chamber 6a.- takes place via another hole lain the adjacent end wall. of the casing 4, and a bore l19'a in. the

exhaust box which'bore l9a discharges into the atmosphere and extendsperpendicular to the aforesaid bore I'Ib. These two bore portions Ilband l9a terminate at their outer ends in a common bore 20 in which aplug valve 2| (Figures 4 and 5) is rotatably accommodated and containstwo semi-cylindrical recesses or ports I10 and 19b corresponding to thebore portions Ill: and 19a respectively and positioned within theirrespective bore portions. Accordingly, as the latter extendperpendicular to one another the valve plug, inone extreme positionthereof, and as illustrated in Figure 4, completely closes the outletend of the bore portion I90 and completely opens the outer end of thebore portion l'lb to the atmosphere as in this position of the plugvalve the semi-cylindrical recess or port ISD is disposed 'silfe in theouter turbine chamber 6a and a screwed plug valve for obtaining anadjustable but set pressure condition in the other turbine chamber 0.

The: push button 22. is. carried at the free end of a spring strip 23which. is secured at its opposite end, by screws 24, on the one endplate 25 of the drill casing 4, which end plate is detachably mounted.in position and corresponds to the outer turbine chamber 6a, the exhaustfrom which takes place via a pair of openings 26 28a in the said endplate. The spring strip urges the press button outwards into. theposition seen in. Figure 11 where the exhaust opening 26 is open to theatmosphere but the arrangementv is such that this. opening can beimmediately closed, whenever required, simply by pressing upon the pressbuttonv 22 and holding the same depressed. The opening 25 is a simpleopening and is normally open to the atmospherev whereas the otherexhaust opening 26a for the one turbine chamber 60. is a compositeopening and. includesv an outer opening. 26b at right. angles to theopening 25a and discharging into the atmosphere from an intermediate,bore 21 containing a screw, and spring biassed, plug. 28 by which theeffective size of these exhaust openings may be varied and set to a.desired amount- The exhaust from the other turbine chamber 6 takes placevia an opening 29 in the corresponding end wall 33 of the turbine casing4, which opening 29 communicates with a bore 30 containing a branchopening 3.! and fitted with a screw plugv 32 which is adjustable and set(normally permanently) to give a. desired pressure in this turbinechamber 6..

The invention provides a novel form of drilling machine or head thereforwhich eliminates the human element and permits the machine to be setonce and for all by a skilled person togive the correct feeding.movement automatically so that this is thereafter independent of anyerrors of judgment. on the part of the operator.

I claim:

1.. A fluid motor device comprising in combination a spindle, a turbinerotor of disc form at one end of the spindle, a set of turbine vanesdisposed on each side of said rotor disc, a stationary casing in whichsaid rotor is accommodated and which is divided thereby into twoseparate turbine chambers each having its own inlet and exhaustpassages, the rotor andspindle being mounted in said casing for bothrotary and reciprocatory movements relatively thereto, and means forvarying the fluid pressure in one or the other of said chambers wherebyto produce an axial movement of the spindle.

2. A fluid motor device according to claim 1 wherein each set of turbinevanes is provided with its own jet and exhaust system and means isprovided adapted to permit of the selective production of an increasedpres re Within one or the other turbine chambers whereby, depending uponthe side on which such increase in pressure is selected to take place,the spindle will be moved longitudinally either forwards or backwards.

3. A fluid motor device according to claim 1 wherein means is providedfor restricting the exhaust from one of the turbine chambers so as toproduce automatically a reciprocatory movement of the spindle.

4. A fluid motor device according ,to claim 1 wherein the exhaustpassages from the turbine chambers deliver into a common bore. and avalve in said common bore which is rotatable to vary the effective sizeof said exhaust passages.

5. A fluid motor device according to claim 1 wherein the exhaust systemof one of the turbine chambers includes a normally open exhaust openingand a spring biased press button associated with said exhaust openingand capable of being depressed to close the opening momentarily.

6. A fluid motor device comprising in combination a casing having ahollow chamber therein, a turbine rotor mounted in said chamber for bothrotational and reciprocatory movement therein, a spindle carried by saidrotor to extend outwardly from said chamber, the latter having inlet andexhaust openings for the propulsive fluid and means for varying thefluid pressure on one side or the other of said rotor to producesimultaneously both rotary and translational movement of the spindle,-

'7. A fluid motor device comprising in combination a stationary casinghaving a cylindrical chamber therein and extending outwardly from thecentre of one side of this cylindrical chamber, a hollow tubular partcoaxial with the cylindrical chamber, a spindle mounted in said tubu larpart to extend longitudinally thereof and coaxial therewith, the innerend of the spindle extending into the cylindrical chamber and thespindle being mounted to have both rotary and axial movement relativelyto the tubular casing part, a turbine rotor secured upon the inner endof the spindle to extend transversely across the cylindrical chamberanddivide the latter into two separate compartments located one on eachside of the rotor, the latter having blade means on each side thereofand each said compartment having its own fluid inlet and exhaustopenings and means for varying the fluid pressure in one or the other ofthe said compartments to produce an axial movement of the spindle in therequired direction.

PERCY WHITE.

